THE INCORPORATION OF C14 INTO CELLULOSE AND OTHER POLYSACCHARIDES OF SUGAR BEET LEAF DURING SHORT TERM PHOTOSYNTHESIS IN C14O2

1962 ◽  
Vol 40 (1) ◽  
pp. 1-11 ◽  
Author(s):  
D. C. Mortimer ◽  
Clare B. Wylam
Keyword(s):  
Carbon Dioxide ◽  
Sugar Beet ◽  
Potassium Hydroxide ◽  
Soluble Fraction ◽  
Short Term ◽  
Photosynthetic Assimilation ◽  
To Receive ◽  
Hydrolysis Of ◽  
Soluble Fractions

The carbohydrates of sugar beet leaf were fractionated by successive extractions in ethanol, water, and three concentrations of potassium hydroxide. Quantitative hydrolysis of the polysaccharides from the water- and alkali-soluble fractions gave galactose, glucose, arabinose, xylose, ribose, and rhamnose in varying proportions. When these fractions from leaves which had photosynthetically assimilated C14O2 for 10 to 120 seconds were analyzed, all fractions, including the alkali-insoluble cellulose, were labelled after only 10 seconds. The proportion of C14 in the alkali-soluble fraction was high relative to that in cellulose after 10 seconds, but similar in both fractions after longer periods. All of the radioactivity in the carbohydrates was in glucose (apart from the fructose of sucrose). When photosynthesis in C14O2 was followed by photosynthetic periods in normal air, the polysaccharide fractions all continued to receive C14-labelled glucose for about 5 minutes. No significant transfer of radioactivity from one fraction to another was detected during an additional 40 minutes. The data indicate that the formation of leaf polysaccharides is closely linked to early products of the photosynthetic assimilation of carbon dioxide, and that the different polysaccharides are formed concurrently with little interconversion.

Degradation of Pectic Polysaccharides in Pickled Green Olives

1998 ◽  
Vol 61 (1) ◽  
pp. 78-86 ◽  
Author(s):  
CORAL SÁNCHEZ-ROMERO ◽  
RAFAEL GUILLÉN ◽  
ANTONIA HEREDIA ◽  
ANA JIMÉNEZ ◽  
JUAN FERNÁNDEZ-BOLAÑOS
Keyword(s):  
Molecular Weight ◽  
Potassium Hydroxide ◽  
Soluble Fraction ◽  
Water Soluble ◽  
Low Molecular Weight ◽  
Pectic Polysaccharides ◽  
Water Soluble Fraction ◽  
Molecular Weights ◽  
Extraction Agent ◽  
Soluble Fractions

The changes that occur in the pectic fractions in the cell wall of olives of the Manzanilla variety (Olea europaea pomiformis) during processing (initial treatment at high pH and subsequent lactic fermentation) have been researched. After studying various conditions for fractionating the pectic polysaccharides, the most adequate were chosen, involving sequential extraction with water, imidazole-hydrochloric acid buffer, sodium carbonate, 1 M potassium hydroxide, and 4 M potassium hydroxide. In the unprocessed fruit, the fractions studied consist mainly of high-molecular-weight acidic polysaccharides (70 to 250 kDa): homogalacturonans, rhamnogalacturonans, and branched arabinans. These were found in different proportions depending on the extraction agent used. At the same time, significant amounts of relatively low-molecular-weight (10 to 10.5 kDa) neutral branched arabinans were found in the water-soluble fraction. As a result of the processing, changes occurred in the proportions of the different groups of polysaccharides in accordance with changes in their solubility characteristics. These changes were reflected in the processed fruit by (i) an increase in the neutral branched arabinans in the water-soluble fraction due to the increased presence of such polysaccharides originally found in the carbonate and 4 M KOH-soluble fractions; (ii) an increase in homogalacturonans and rhamnogalacturonans, without significant changes in molecular weights, in the imidazole-soluble fraction as a result of the increased presence of corresponding polysaccharides originally found in the carbonate-soluble and water-soluble fractions; (iii) a substantial increase in uronic acids in the 1 M potassium hydroxide-soluble fraction, preferentially as low-molecular-weight polysaccharides; and (iv) a solubilization of arabinans in the 4 M potassium hydroxide-soluble fraction.

SOME SHORT-TERM EFFECTS OF INCREASED CARBON DIOXIDE CONCENTRATION ON PHOTOSYNTHETIC ASSIMILATION IN LEAVES

1959 ◽  
Vol 37 (6) ◽  
pp. 1191-1201 ◽  
Author(s):  
D. C. Mortimer
Keyword(s):  
Carbon Dioxide ◽  
Plant Species ◽  
Closed System ◽  
Carbon Dioxide Concentration ◽  
Experimental Period ◽  
Glyceric Acid ◽  
Short Term ◽  
Radioactive Carbon ◽  
Photosynthetic Assimilation ◽  
Atmospheric Level

The photosynthetic assimilation of radioactive carbon dioxide by leaves from seven plant species was continuously measured in a closed system in which the concentration of carbon dioxide was abruptly increased from the atmospheric level to predetermined levels up to 2.0%. The rate of assimilation immediately increased, approximately proportional to concentration, but after about one minute began to decrease. The degree and duration of the decrease in rate of uptake varied with plant species and with concentration. This increased uptake of carbon dioxide influenced the distribution of carbon among the products of assimilation. At the lowest concentration (0.1%), serine, glycine, and glyceric acid contained most of the carbon assimilated during the experimental period, but at higher concentrations these were replaced by sucrose and alanine.

SOME OBSERVATIONS ON THE FORMATION OF GLYCERIC ACID DURING PHOTOSYNTHESIS EXPERIMENTS

1961 ◽  
Vol 39 (1) ◽  
pp. 1-5 ◽  
Author(s):  
D. C. Mortimer
Keyword(s):  
Enzymatic Activity ◽  
Glyceric Acid ◽  
Short Term ◽  
Alternate Pathway ◽  
Phosphoglyceric Acid ◽  
Soybean Leaf ◽  
Photosynthetic Assimilation ◽  
Hydrolysis Of

The dephosphorylation of phosphoglyceric acid was tested under a variety of conditions. Hydrolysis of the ester by leaf homogenates was relatively slow, even when conditions favored enzymatic activity, and was not detected when frozen homogenate was extracted by boiling 80% ethanol. The results suggest that glyceric acid recovered in ethanol-soluble extracts of leaves following short-term photosynthesis experiments is not normally derived from phosphoglyceric acid. The route proposed for the synthesis of glyceric acid is related, with particular reference to soybean leaf, to an alternate pathway for photosynthetic assimilation which does not utilize phosphoglyceric acid.

HEMICELLULOSES OF WHEAT STRAW

1951 ◽  
Vol 29 (2) ◽  
pp. 109-122 ◽  
Author(s):  
G. A. Adams ◽  
A. E. Castagne
Keyword(s):  
Wheat Straw ◽  
Potassium Hydroxide ◽  
Uronic Acid ◽  
Degree Of Polymerization ◽  
Water Soluble ◽  
Hot Water ◽  
Acid Complex ◽  
Main Fraction ◽  
Hydrolysis Of ◽  
Soluble Fractions

Various hemicellulose fractions were extracted from wheat straw holocellulose (extractive and pectin free) by successive treatments with cold and hot water, 0.5%, 1.0%, and 2.0% potassium hydroxide and were recovered by precipitation with alcohol. Approximately 25% of the holocellulose material was removed, one half being in the hot water soluble fraction. The original holocellulose, the extracted residue, and the recovered fractions were analyzed for pentosan, uronic acid anhydride, acetyl, methoxyl, and ash content. In general, the more soluble fractions had a higher uronic acid and methoxyl content; the less soluble had a higher pentosan content and a more negative rotation [Formula: see text]. Intrinsic viscosity measurements indicated that all fractions had a degree of polymerization of 25–30. Hydrolysis of the main fraction yielded D-xylose, L-arabinose, D-glucose; in addition D-galactose was found in the water soluble fractions. Quantitative determinations of the sugars in the hydrolyzates showed that D-xylose predominated, with L-arabinose, D-glucose, and D-galactose (when present) in progressively smaller amounts. On hydrolysis all fractions yielded an acid-resistant uronic acid complex that contained D-xylose and a uronic acid tentatively identified as monomethoxyl galacturonic acid.

Short-term variation in fluxes of carbon dioxide, nitrous oxide and methane in cultivated and forested organic boreal soils

2002 ◽  
Vol 34 (5) ◽  
pp. 577-584 ◽  
Author(s):  
Marja Maljanen ◽  
Pertti J. Martikainen ◽  
Heikki Aaltonen ◽  
Jouko Silvola
Keyword(s):  
Carbon Dioxide ◽  
Nitrous Oxide ◽  
Short Term ◽  
Term Variation ◽  
Boreal Soils

Urea hydrolysis and inorganic N in a Luvisol after application of fertiliser containing rare-earth elements

Soil Research ◽  
2003 ◽  
Vol 41 (4) ◽  
pp. 741 ◽  
Author(s):  
Xingkai Xu ◽  
Zijian Wang ◽  
Yuesi Wang ◽  
Kazuyuki Inubushi
Keyword(s):  
Rare Earth ◽  
Rare Earths ◽  
Substantial Reduction ◽  
Application Rate ◽  
Urea Hydrolysis ◽  
High Rate ◽  
Short Term ◽  
N Content ◽  
N Fertilisers ◽  
Hydrolysis Of

In recent decades, Chinese agriculturists have used rare-earth-containing fertilisers as basal fertilisers together with N fertilisers (e.g. urea). We studied urea hydrolysis and its hydrolysis products in a laboratory experiment using urea-N fertiliser with rare earths at rates from 0.5 to 50% (w/w). The results indicated that application of rare earths at a high rate could result in a short-term inhibition of urea hydrolysis and an increase in soil (NH4+ + NO3– + NO2–)-N content. When the application rate of rare earths was higher than 5% of the applied urea-N (corresponding to 10 mg/kg soil), soil exchangeable NH4+-N content increased significantly following the hydrolysis of the applied urea. Increasing the application rate of rare earths appeared to reduce the content of soil urea-derived (NO3– + NO2–)-N. A substantial reduction in soil pH was found immediately after application of rare earths and urea. We conclude that application of rare earths at >10 mg/kg may lead to a substantial increase in the content of urea-derived N in the soil, via the inhibition of urea hydrolysis and nitrification.

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